Known as one of techniques for directly producing a strip from molten metal is twin roll continuous casting where molten metal is supplied to between a pair of horizontally juxtaposed rolls to deliver a solidified metal strip.
FIGS. 1-3 show an example of a twin-roll casting machine with a pair of chilled rolls 1 horizontally juxtaposed and a pair of side weirs 2 associated with the rolls 1.
The chilled rolls 1 are constructed such that cooling water passes through insides of the rolls and a nip G between the rolls is increased/decreased depending on thickness of a steel strip 3 to be produced.
Rotational directions and velocities of the rolls 1 are set such that outer peripheries of the respective rolls 1 are moved from above toward the nip G at constant velocity.
One and the other of the side weirs 2 surface-contact one and the other ends of the respective rolls 1, respectively.
Arranged between the paired side weirs 2 is a melt supplying nozzle 4 so as to be positioned just above the nip G. Molten steel is poured from a ladle (not shown) to the nozzle 4 to supply the molten steel in a space defined by the rolls 1 and side weirs 2. Thus, a melt pool 5 is provided.
Specifically, the above-mentioned melt pool 5 is formed and the chilled rolls 1 are rotated with the cooling water passing through and cooling the rolls 1, so that molten steel is solidified on outer peripheries of the rolls 1 and steel strip 3 is delivered downward from the nip G.
In this case, forces are applied to bearing boxes (not shown) for rotary support of necks of the respective rolls in directions toward each other so as to make the steel strip 3 to have a targeted thickness value.
The side weirs 2 are pushed by pressing actuators such as hydraulic cylinders against ends of the rolls 1 to prevent leaking of the molten steel (see, for example, Patent Literatures 1 and 2).                [Patent Literature 1] JP 2000-190053A        [Patent Literature 2] JP 2004-050252A        